This is a paid asset, but now you can download Underworld: Cave Environment for FREE, Please keep in mind this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Detail this asset from Unity Store: Original Link
Underworld: Cave Environment v1.31 (Latest version)
Extensive package for easy creation of complex underground. Modular components allow you to create large levels – quickly and easily.
Pack contains:
– 105 prefabs (258 – including LoD stages) – caves, rocks, crystals, mushrooms etc.
– 29 ready-to-use modules
– One big demo stage
– 7 particles
Almost all textures are at 2048×2048 resolution. The materials have normalmaps, in some cases, bumpmaps to paralax shading.